A Study to Evaluate the Efficacy and Safety of Bimekizumab in Subjects With Active Nonradiographic Axial Spondyloarthritis

Inclusion Criteria

• Male or female patients at least 18 years of age
• Patient has nonradiographic axial spondyloarthritis (nr-axSpA) with all of the following criteria:
• Adult-onset axial spondyloarthritis meeting Assessment of SpondyloArthritis International Society (ASAS) classification criteria
• Inflammatory back pain for at least 3 months
• Age at symptom onset of less than 45 years
• NO sacroiliitis (in Anterior-Posterior pelvis or sacroiliac x-ray)
• Active disease defined by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) >=4 AND spinal pain >=4 on a 0 to 10 Numeric Rating Scale
• Objective inflammation defined by sacroiliitis on magnetic resonance imaging and/or elevated C-reactive protein
• Subjects had to have either failed to respond to 2 different nonsteroidal anti-inflammatory drugs (NSAIDs) given at the maximum tolerated dose for a total of 4 weeks or have a history of intolerance to or a contraindication to NSAID therapy
• Patients who have taken a tumor necrosis factor alpha (TNFα) inhibitor must have experienced an inadequate response or intolerance to treatment given at an approved dose for at least 12 weeks
• Patients currently taking NSAIDs, cyclooxygenase 2 (COX-2) inhibitors, analgesics, corticosteroids, methotrexate (MTX), leflunomide (LEF), sulfasalazine (SSZ), hydroxychloroquine (HCQ) AND/OR apremilast can be allowed if they fulfill specific requirements prior to study entry

Exclusion Criteria

• Treatment with more than 1 TNFα inhibitor and/or more than 2 additional non-TNFα biological response modifiers, or any interleukin (IL)-17 biological response modifier
• Active infection or history of recent serious infections
• Viral hepatitis B or C or human immunodeficiency virus (HIV) infection
• Any live (includes attenuated) vaccination within the 8 weeks prior to entering the study or TB (Bacillus Calmette-Guerin) vaccination within 1 year prior entering the study
• Known tuberculosis (TB) infection, at high risk of acquiring TB infection, or current or history of nontuberculous mycobacterium (NTMB) infection
• Subject has any active malignancy or history of malignancy within 5 years prior to the Screening Visit EXCEPT treated and considered cured cutaneous squamous or basal cell carcinoma or in situ cervical cancer
• Diagnosis of inflammatory conditions other than axial spondyloarthritis (axSpA), including but not limited to psoriatic arthritis, rheumatoid arthritis, sarcoidosis, systemic lupus erythematosus, and reactive arthritis. Patients with a diagnosis of Crohn's disease, ulcerative colitis, or other inflammatory bowel disease (IBD) are allowed as long as they have no active symptomatic disease when entering the study
• Presence of active suicidal ideation, or moderately severe major depression or severe major depression
• Female patients who are breastfeeding, pregnant, or planning to become pregnant during the study
• Subject has a history of chronic alcohol or drug abuse within 6 months prior to Screening